• Title of article

    U–Pb SHRIMP data constraints on calc-alkaline granitoids with 1.3–1.6 Ga Nd TDM model ages from the central domain of the Borborema province, NE Brazil

  • Author/Authors

    Guimarمes، نويسنده , , I.P. and Silva Filho، نويسنده , , A.F. and Almeida، نويسنده , , C.N. and Macambira، نويسنده , , M.B. and Armstrong، نويسنده , , R.، نويسنده ,

  • Issue Information
    روزنامه با شماره پیاپی سال 2011
  • Pages
    14
  • From page
    383
  • To page
    396
  • Abstract
    The Tabira, Itapetim and Timbaúba granitoids are intruded into metasedimentary sequences and Cariris Velhos (Tonian) orthogneisses from the Central Domain of the Borborema Province, NE Brazil. They have U–Pb SHRIMP ages of 593 ± 7 Ma; 615 ± 9 Ma and 616 ± 5 Ma respectively. The studied granitoids have zircon cores inherited from the protholith, with a large number of analyses showing 206Pb/238U ages ranging from 950 to 1200 Ma. Oscillatory zoning typical of magmatic zircon is common, although it is faint in some inherited cores. udied granitoids are calc-alkaline and show Nd TDM model ages ranging from 1.30 to 1.56 Ga and ɛNd (600 Ma) ranging from −2.40 to −5.34. These values are similar to those recorded in the country rocks. The lowest values of ɛNd (600 Ma) were recorded in enclaves of dioritic composition. Nd and U–Pb SHRIMP data suggest a significant participation of the metasedimentary rocks in the protholith of these granitoids. The Mesoproterozoic Nd TDM model ages recorded in the studied granitoids are interpreted as the result of a hybrid source involving melting of metagraywackes, metamafic rocks of Tonian ages and/or biotite – bearing orthogneisses (Cariris Velhos Orthogneisses). The resulted melting was modified by mingling with juvenile Brasiliano melts, diorite in composition. mbaúba granitoids intrusions are coeval with high-T metamorphism and flat-lying foliation forming event in an intracontinental setting, during the Brasiliano convergence and contractional deformation. The Itapetim Pluton was emplaced in the convergence - lateral escape setting and the Tabira granitoids were intruded after the flat-lying foliation event, representing sin transcurrent intrusions. ta show that within the Central Domain of the Borborema Province, granitoids with similar petrographic and geochemical compositions can have distinct ages and be intruded in distinct tectonic regimes.
  • Keywords
    Granitoids , Brasiliano , Source Rock , U–Pb SHRIMP data
  • Journal title
    Journal of South American Earth Sciences
  • Serial Year
    2011
  • Journal title
    Journal of South American Earth Sciences
  • Record number

    2239991